The goal of this program is to develop a non-contacting array of bioelectrodes for monitoring EEG, EOG, EMG and ECG on the head. By non-contacting we mean that the bioelectrodes are not in contact with the skin but can be separated by a small air gap, or located on the outer surface of a cap or patch worn by the patient. The proposed new system builds on a new class of sensor that can measure the electric potential of free-space at the microvolt level. A September 2002 clinical trial showed that when operating through a cotton shirt small bioelectrodes based on the new sensor have > 99% correlation with a conventional skin contact electrode. The aims of this program are to study and overcome artifacts associated with using these sensors in close proximity to the head, to develop a complete system for sleep monitoring using the minimum number of sensors, and to test the technology in the Sleep Research Laboratory at Stanford University. The proposed bioelectrode array is completely new and offers a new modality for standoff measurement of physiologic signals, providing the capability to work with minimal or no skin preparation, and increased safety (the electrodes do not make electrical contact). It should be possible to build the electrodes onto the outside of a cap or shirt to provide greatly increased comfort and wearability. The system would provide a major improvement in comfort for sleep studies, providing minima disturbance to the patient and the capability for long term at-home monitoring. In addition, the new system will also find wide application in many other areas of clinical care that involve long and short term monitoring of ECG, EEG, and EMG signals, and should make possible a new of new systems for outpatient monitoring. Potential applications include research and clinical instrumentation for sleep monitoring, systems for at-home monitoring of sleep, continuous physiologic monitoring of EEG and ECG activity, non-contact bioelectrodes for burn victims, rapidly applied ECG detectors for emergency response teams, and self-applied ECG sensors for home care. Further opportunities should exist in alertness monitoring, sporting equipment, and video games.